The traditional production procedure of the color enlarging photo printer is: Put the color negative film into the carrier, the light provided by the light source and the mixed light barrel passes through the color negative film, the enlarging objective lens and forms images on the printing paper. Because the color ingredient on the film is different and the light is corrected by the color filters, the color former on the printing paper receives different light exposure and becomes latent images. The auto-printing equipment will print printing papers to certain amount, which are sent into the processing equipment to react fully with the developer in developer liquid tank, the fixative in fixative liquid tank and the stabilizing bath in the stabilization tank, to finish such procedures as developing, fixing and stabilizing. The printing papers are dried and cut automatically to get vivid color photos.
The work process of the traditional color enlarging photo printer has existed for a long time. In China, thousands of such equipments are distributed all over the country. In these years, with the development of digital technology, the traditional film photography is being replaced gradually by the digital photography technology for its shortcomings such as high cost, unable to see the quality of the photos immediately and so on.
An existing digital exposure apparatus is shown in FIG. 1. The digital exposure apparatus replaces the negative film carrier on the color enlarging photo printer, being fixed on the color enlarging photo printer in the same matter as the negative film carrier. The color enlarging photo printer can be used to print traditional films and digital images. The digital images can be corrected or edited using computer, displayed by Liquid Crystal on Silicon and projected onto the printing paper to exposure and get the digital photos. The inherent color enlarging photo printer has been provided with more functions.
The digital exposure apparatus comprises: a printing lamp 11, a filters 12, a mixed light barrel 13, an exposure component 14, a shutter 15; the exposure component 14 comprises: a polarization splitting prism 141, a second enlarging lens 142, a Liquid Crystal on Silicon 143, an enlarging lens 144, a light source 145, a first reflective mirror 146, a second reflective mirror 147, a third reflective mirror 148, a second shutter 149. The light source 145 comprises: a halogen lamp 1451, a heat absorbing glass 1452, a falling color temperature reduction glass 1453, a mixed light barrel 454, a second filter 1455, a condenser lens 1456. The printing lamp irradiates light to pass through the heat absorbing glass and the falling color temperature reduction glass into the mixed light barrel to uniform the light; the red, green, and blue color lights are produced while passing through the second filter; the condenser lens magnifies the facula, uniformly irradiates the light onto the polarization splitting prism; which reflects the three-color images engendered by the Liquid Crystal on Silicon, the enlarging objective lens magnifies the images; the first, second and third reflective mirrors reflect the light and to images at the negative position, which are in the size of the traditional 135 color film. The enlarging objective lens magnifies the image. At last, the color photos are formed on the printing paper 16. Since the digital exposure apparatus replaces the initial negative carrier, the position of the digital image displayed by the chip will be at the place where the color negative film is, meaning that it can be treated as a negative. For this reason, the imaging sources can be expanded to the digital images of disks, digital cameras, not only the color negative films as before. Combined with other functions of the color enlarging photo printer, this apparatus can be used both in film printing and digital printing. It is devised to acclimate with the today's trend in photography and promotes the development of photography. But in this apparatus, there are too many reflective mirrors, the optical axis of the second enlarging lens and the enlarging objective lens can not be adjusted easily, especially doing installation at the printing house. Also because there are too many lenses composed by the second enlarging objective lens and the enlarging objective lens, the light intensity radiated by the printing lamp loses a lot due to the absorption of the glasses, the exposure time is prolonged and the velocity is affected.